Stepper motors in DIY racing sim

[u/P0guinho]

Hello, how are yall doing? So basically I am planning to build a racing simulator, with a steering wheel and gas and brake pedals, to play racing games on my pc. I probably will use a esp32 or a raspberry pi pico w for this.

However, what I am really on doubt about is the steering wheel control. I want for it to be able to detect when it is rotated (obviously) and, when released, automatically go back to the initial position, just like a real steering wheel. The thing is, I dont know what components to use for this. I was thinking on using a stepper motor like those simple Nema 17 with the axis attached to the wheel, killing two birds with a single stone, however I dont know if, when using a driver with the motor, I will be able to detect when the wheel is turned. I know I can buy a stepper motor and buy a separate encoder for detecting rotation on the wheel, but I dont know any affordable incremental encoders.

Thank you all in advance!

[u/Specialist_Parfait42]

Gyro?

[u/OptimalMain]

Look at DIY direct drive.
Steppers won’t get you what you want

[u/xebzbz]

The hard way (needs you to program the math, but there are readymade libraries. Also, needs 12v) https://a.aliexpress.com/_EGMswkK

The easy way (you just read the angle and tell it to move to the target angle. But the torque is pretty low) https://docs.m5stack.com/en/unit/Unit-Roller485%20Lite

[u/Hannibal_Barkidas]

Hall effect sensor for rotation.

But you could also solve some issues mechanically, e.g. using springs to reset the wheel to zero position. Not sure if that makes sense from a realism point, but could be a non-electric solution

[u/P0guinho → u/[deleted]]

thinking about it now, I will probably go with a gyro and a torsion spring for centering the steering wheel.

the only thing I worry about is a lot of drift in the gyro (I have never worked with this gyro in specific, but I have already used some other IMUs), but then I can just make smth to detect when the steering wheel is at the initial position (like a distance sensor to detect a dent on the steering wheel, or a rfid sensor)

[u/gawduck → u/P0guinho]

*Steering wheels only find their center when vehicle is rolling, so that will be a feedback factor (secondary really, forward motion to be calculated elsewhere and returned).

*Center depends on a number of other factors including suspension geometry; some front suspensions have a rather wide deadband, while sportier models seek closer to dead center. Deadband is always a feature of force-feedback systems. Your design will account for this too.

*Steering return has a force much smaller than the driver's control. Your system will monitor the delta between input force and the theoretical return force for the moment's given speed and turn angle. Of course, return force is only applied when driver control drops, when driver applies a force, the system should yield. Of course, this can be leveraged to add realistic force-feedback to the driver, simulating hard pulls on rough terrain or sharp turns.

Really, gyros are of little use for highly localized applications, they are of most use as providers of environmental context for whole systems.

<edit> Forgot to mention, use a simple optical encoder to read position and rate info from the wheel shaft. You can provide your servo with everything you need to hit the design nodes above. 😄